Protective Shield

Protective shield for temperature sensors

The IMI CCI protective shield has been developed to improve temperature measurement stability by protecting temperature sensors installed in the steam pipe from being hit by spray water droplets. A successful temperature control system depends on accurate and reliable measurements of steam temperature. In applications where the temperature sensor is installed close to a desuperheating arrangement, like that of a steam conditioning valve and/or in situations where there is a risk of water droplets that have yet to evaporate hitting the temperature sensor, IMI CCI recommends installing a protective shield.

• When a temperature sensor is hit by free water droplets, it causes a misreading of the steam temperature. The misreading can be large enough to read at saturation temperature. This causes the temperature control loop to close the spray water valve. When the spray water valve closes, the temperature sensor reads uncooled steam temperature, which prompts the temperature control loop to once again open the valve. In worst case, this could cause major temperature oscillations, as shown in the graph below. The IMI CCI protective shield minimises this effect and improves loop stability, though in some cases it might cause delays in temperature readings. Many variables are important to take into consideration when installing temperature sensors, such as the distance to any desuperheating arrangement, drainage, pipe bends, etc.

• Protects temperature sensors.
• ASME/ASTM or EN standards available.
• Welded, threaded or flanged connection.